Black screen upon start up on windows 7

Hello, I have a frustrating problem ever since I did windows critical update and changed anti virus and the problem occurred yesterday. Every time I reboot my PC, a black screen appears with a cursor shows up for a few minutes before going onto login screen/welcome screen. I did system restore back to a month and it still doesn't work. I uninstalled anti virus to see if that might be the case and the black screen is still there. I then reformatted my pc by reinstalling windows 7 again using the disc and the problem is still there. My pc is only one year old as well and it's quite fast and quiet. Normally when I startup my PC it goes straight onto the welcome screen/desktop without this black screen.
What can I do in this case? Much help will be appreciated.

When you say cursor, you mean mouse pointer?
Unplug any devices not absolutely necessary, take any discs out of your optical drive if there's one in there - any difference?
What antivirus did you remove, which one are you using now? Did you reinstall Win 7 from a recovery disk, along with bundled software that came with your PC or was it from a plain ol' OEM/Retail Windows 7 DVD?

Sorry yes I meant mouse pointer. Still no difference when I took out discs. I removed Norton and I am using bitdefender now. I wasn't sure if it was the anti virus that caused or the recent Windows update.
I reinstalled Windows using the retail DVD, my pc didn't have a recovery disk that came with it. I reinstalled the drivers CD as well.

I have had one or two issues with bitdefender slowing my start up , but only for about 30-40 seconds , but I am using a SSD . my screen staed blue tho . All I did was run the repair feature on bitdefender , this seemed to cure it .